Colin, I've ran the Go .21 in my truggy for a long time, then it dumped on me, and I had a hard time getting it tuned in, so when Russell and I went to the Silverstate, I got a .25 from him to run at the Silverstate, but never got it broke in in time, it's in my other truggy that my son is racing at the truck nats in a couple of weeks, maybe I get get it ready for him to run.